Beta-versions like the recent 6.85 one yeah....you can download and install them manually. The "proper" versions like the 7.20 i don't think you can. At least I've never seen a way to do so. That's what the phased roll-out is for.
It seems that for most customers, their turn to update to 7.2 will be most likely at the end of 2021, if there were no delays, taking into account how things are going with update 7.1 now! Please vote "-1" if you are agree